Reaction Mechanisms Activity: 1. Ask for 7 volunteers 2. Ask them to line up like so 3. Give them different Styrofoam balls 4. Ask them to throw all of the balls into a box that is near them, so that they all hit at the right spots(match the colours) and fast enough that they will bond, and at the same time 5. Explanation: Just as how tough it was for all the reactions to occur at the same time, it is very improbable for reactions that require many molecules to hit and react, because you need the right speed, and orientation 6. That’s why we have intermediate steps 7. Give them back their balls 8. Tell them to pass it along and add their molecules to the right spots and pass it down the line 9. Stop at 3, point out how they will take longer to do their step as they also have to run, with molecules, that reaction requires more energy so it takes longer 10. Let 4 continue, and let the activity complete 11. These steps are elementary reactions and they produce reaction intermediates 12. Some of the people in between are unstable products that will react the as fast as they can, so all of this happens really fast 13. The slowest person, or reaction (#3) is the rate determining step, so they determine the speed of that reaction 14. Basically: each step is elementary so there can be no more than three reactant molecules The rate determining step should be consistent with the rate equation The elementary steps is add up to the overall equation TERMS: Reactions Mechanism: A sequence of elementary steps - a step that only involves 1, 2 or 3 particles colliding Rate Determining Step: the slowest reaction step in a reaction mechanism Reaction Intermediates: products that are formed from the elementary reactions
Activity:
1. Ask for 7 volunteers
2. Ask them to line up like so
3. Give them different Styrofoam balls
4. Ask them to throw all of the balls into a box that is near them, so that they all hit at the right spots(match the colours) and fast enough that they will bond, and at the same time
5. Explanation: Just as how tough it was for all the reactions to occur at the same time, it is very improbable for reactions that require many molecules to hit and react, because you need the right speed, and orientation
6. That’s why we have intermediate steps
7. Give them back their balls
8. Tell them to pass it along and add their molecules to the right spots and pass it down the line
9. Stop at 3, point out how they will take longer to do their step as they also have to run, with molecules, that reaction requires more energy so it takes longer
10. Let 4 continue, and let the activity complete
11. These steps are elementary reactions and they produce reaction intermediates
12. Some of the people in between are unstable products that will react the as fast as they can, so all of this happens really fast
13. The slowest person, or reaction (#3) is the rate determining step, so they determine the speed of that reaction
14. Basically: each step is elementary so there can be no more than three reactant molecules
The rate determining step should be consistent with the rate equation
The elementary steps is add up to the overall equation
TERMS:
Reactions Mechanism: A sequence of elementary steps - a step that only involves 1, 2 or 3 particles colliding
Rate Determining Step: the slowest reaction step in a reaction mechanism
Reaction Intermediates: products that are formed from the elementary reactions